1. Field of the Invention
The present invention relates generally to circuit substrates, and particularly to circuit substrates that utilize conductive contacts along the sides or edges of the substrate.
2. Background of the Related Art
Circuit substrates, such as circuit boards, are electronically connected to other components through conductive contacts disposed in or on the substrate. Conventionally, components were attached to contacts located on the top or bottom surface of the circuit substrate. The components were attached, for instance, by soldering conductive component leads to the appropriate contacts.
As devices utilizing circuit substrates have decreased in size, there has been great demand for miniaturization of the circuit substrate. This demand has prompted attempts to utilize the sides or edges of the substrate for attachment of some components. Accordingly, the conductive contacts to which the components are connected also have been moved to the edges of the circuit substrate.
One approach has been to use screen printed metallization for placing conductive contacts along the edge of a given circuit substrate. The components are then attached to these conductive contacts by known methods.
The screen printing technique can be problematic, because the metallization at each contact is relatively thin, which can lead to excess material leaching. The end result is loss of adhesion between the conductive contact and the attached component. Additionally, the relatively thin metallization allows for only limited rework applications before undue degradation of the conductive contact.
It would be advantageous to have thicker, more durable conductive contacts along the edges of a circuit substrate to facilitate attachment of various components thereto.
The present invention includes a method for providing metallized conductors along the edge of a circuit board. The method includes stacking a plurality of uncured layers of a circuit substrate, and forming at least one via through the plurality of layers. The method also includes filling the at least one via with a metallized conductive material; covering the at least one via with a cover layer; and providing a vent to the at least one via to exhaust any gases created during processing.
According to another aspect of the invention, a method is provided for creating a circuit board substrate with edge connectors. The method includes providing a bottom layer of a green laminate. The method further includes stacking a plurality of layers of the green laminate on the bottom layer, and aligning apertures in each layer of the plurality of layers to create a via. The method also includes filling the via with a conductive material, and connecting a vent to the via for exhaustion of byproduct gases during firing of the green laminate.
According to yet another aspect of the invention, a method is provided for creating a circuit board with a buried edge connector. The method includes creating a via within a plurality of layers of a laminate. The method also includes filling the via with a conductive compound, venting the via, and curing the laminate. Additionally, the method includes dicing the laminate through the via to expose the conductive compound along an edge of the laminate.